The researchers found three times the PGD2 in bald scalp than in haired scalp of men with androgenetic alopecia. When PGD2 was added to cultured hair follicles, PGD2-treated hair was significantly shortened, while PGD2's derivative, 15-dPGJ2, completely inhibited hair growth. This inhibition of hair growth also occurred in mouse models. The PGD2-related inhibition occurred through a receptor called GPR44, which is a promising therapeutic target for androgenetic alopecia in both men and women with hair loss and thinning, according to the researchers.

A different prostaglandin (F2alpha) is known to increase hair growth. Researchers found that as PGD2 inhibits hair growth, other prostaglandins work in opposition, enhancing and regulating the speed of hair growth. While these studies looked at androgenic alopecia in men, the researchers noted that prostaglandins may represent a common pathway shared by both men and women with the condition. Future studies, potentially testing topical treatments that may target GPR44, can determine whether targeting prostaglandins will benefit woman with androgenic alopecia as well.

In 2011, a related study was published by the university in the Journal of Clinical Investigation where underlying hair follicle stem cells were found intact, suggesting that the scalp was lacking an activator or something was inhibiting hair follicle growth.

The study was funded by grants from the National Institutes of Health, the Pennsylvania Department of Health, the Edwin and Fannie Gray Hall Center for Human Appearance at Penn Medicine, American Skin Association, Dermatology Foundation and L'Oréal.